问题 填空题

寒冷的冬天,戴眼镜的小明同学在进入温暖的室内时眼镜片上蒙上了一层雾气,雾气的形成是______现象(填物态变化名称).在此现象形成的过程中要______(填“吸热”或“放热”).

答案

冬天室内的温度很高,使周围空气中的水蒸气温度升高,遇到戴眼镜同学温度较低的玻璃镜片时,热的水蒸气发生液化现象变成小水珠附着在镜片上,所以镜片上出现雾气;在液化过程中需要向外放热.

故答案为:液化;放热

阅读理解

阅读理解。

     Plants are very important. This is because plants can make food from air, water and sunlight. Animals

and man can not make food from air, water and sunlight. Animals can get their food by eating plants and

animals. Man gets his food by eating plants and animals, too. So animals and man need plants in order to

live. This is why there are so many plants around us.

     There are two kinds of plants: flowering plants and non-flowering plants. You can know some trees

from their flowers and fruits. Non-flowing plants do not grow flowers. You can not see many non-flowering

plants around you.

     If you look carefully at the plants around us, you will find that there are many kinds of plants. Some

plants are large and some are small. Most of them are green. Thanks to (多亏了) the plants around us we

can live on the earth.

1. Which of the following is the most important to man according to the passage?

A. Fruits.

B. Plants.

C. Animals.

D. Flowers.

2. We need many plants around us because _______.

A. plants can grow easily

B. plants are green

C. we can get what we need from plants

D. we like all kinds of-plants

3. There are much _______ non-flowering plants than flowering plants around us.

A. fewer

B. more

C. larger

D. better

4. Which of the following is TRUE?

A. People can make food from air,water and sunlight.

B. Animals get their food only from eating smaller animals.

C. We know all trees from their flowers.

D. Most of plants are green.

5. The best title for this passage is _______.

A. Food from Plants

B. Plants and Man

C. Man and Animals

D. Plants around Us

单项选择题